The Association between obstructive sleep apnea on diabetic kidney disease: A systematic review and meta-analysis

Study Objective: This systematic review aims to investigate the association between obstructive sleep apnea (OSA) and diabetic kidney disease (DKD). Methods: MeSH terms and free text searches were performed on MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from inception to April 2015. Zetoc and OpenGrey databases were queried for grey literature, and lastly, hand searches were carried out. Study selection and quality assessment were conducted by two authors. One author carried out data extraction, which was checked by other authors. The relationships between apneahypopnea index (AHI), oxygen desaturation index (ODI), time spent under 90% oxygen saturation (%TST < 90), and minimum and mean oxygen saturation (O2) on DKD were examined. Results: Two longitudinal and ten cross-sectional studies were included for our narrative synthesis, and seven studies for meta-analysis. Studies that performed multi-variable analysis demonstrated significant associations between OSA (assessed using either apnea-hypopnea index or ODI) and DKD in type 2 diabetes mellitus (T2DM). This was confirmed by meta-analysis (pooled OR 1.73, 95% CI: 1.13-2.64). There was some evidence to suggest that %TST < 90 may have an association with DKD. There was insufficient evidence to conclude on the relationship between minimum and mean oxygen saturation on DKD. There was no evidence available on the associations between OSA and other respiratory parameters in type 1 diabetes mellitus populations. Conclusions: There is moderate evidence that OSA is associated with DKD in patients with T2DM. Large prospective studies with long-term follow up are needed to assess the possible bi-directional mechanisms between OSA and DKD.